html,body,div,ul,ol,li,dl,dt,dd,h1,h2,h3,h4,h5,h6,pre,form,p,blockquote,fieldset,input
{
    margin: 0;
    padding: 0;
}
body {
    width:100%;
    height:100%;
}
.mainContainer {
    width:630px;
    height:100%;
    background:blue;
    margin-left:auto;
    margin-right:auto;
}
#div1 {
    width:600px;
    height:10%;
    background:red;
    margin-left:auto;
    margin-right:auto;
}
#div2{
    float:left;
    width:210px;
    height:50%;
    background:yellow;
    margin-left:2px;
    
}
#div3{
    float:right;
    width:210px;
    height:50%;
    background:green;
    
}
#div4 {
    float:right;
    width:210px;
    height:50%;
    background:aqua;
    
}
#div5 {
    clear:both;
    width:600px;
    height:10%;
    margin-left:auto;
    margin-right:auto;
    background:brown;
}
#div6 {
  
    width:600px;
    height:20%;
    margin-left:auto;
    margin-right:auto;
    background:chartreuse;
}

